CBSE

If you fail in one subject like Math out of the six subjects in your CBSE board exam, then that may affect your eligibility to give the CUET or CUCET. In fact, eligibility criteria for both CUET and CUCET are different and for undergraduate courses, they require all candidates to pass in all the subjects in Class 12.

In order to change your surname to an initial after you complete your CBSE 12th, you would have to get your name rectified in the official documents before you participate in counseling in JoSAA. First, contact your respective CBSE regional office to request a name change for your Class 12 mark sheet.

If an editing window is available for the KCET application, you must make use of it to rectify the syllabus information. This will ensure that all the information regarding you is correct and matches your actual educational background.
Having the proper information is always beneficial, and in the event where there might be some incongruity that may develop during the admissions process.

Yes, NITs will accept your improved score only if you have only 73% in your 12th borad. You are adviced to appear for improvement exams only if you are from general category as the minimum requirement to appear for JEE is 75% for general. But if you are from other category such as SC/ST, you need not to appear for improvement exam as you're already eligible for JEE. So the answer of your question is yes, the NITs will consider your improved score only and you're adviced to appear for improvement exam only if you're from general category. 

Firstly you have to Understand the exam format, prioritise high-weightage topics. Plan realistic study schedules, factor in breaks to prevent burnout. Tackle challenging subjects during peak focus hours, save lighter revisions for later.

If your class 12th percentage is around 90-95% and 80% in JEE Mains, then you have good chances to get into SASTRA University.

30% of the Engineering seats shall be based on Class XII Aggregate and 70% on the combined Class XII aggregate & 1st JEE Main Scores (75%:25% basis). For all remaining UG programmes (including Law), admissions based on Aggregate Class XII Scores.

If you have been unwell and thus could not sit for Class 12 CBSE exams, and are likely to take it next year, then seek the fees refund from the school itself. Schools do have procedures in place when students, on valid medical grounds, cannot sit for exams. You may be required to fill out a registration form for the following year and pay the registration fees, which are INR 1500 for five subjects with extra fees for additional subjects. Request your school administration to clarify any fee exemptions or reduction.